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In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.

Daikin Altherma/Low Temp Baseboard

I spoke with someone from Daikin and they mentioned 'Low-Temp Baseboard' as an alternative even to cast iron radiators. (I know most on this site are big fans of the low water temps oversized rads afford--in my case 2 to 1 ratio.) I was told low-temp baseboard can emit 800btus of heat per ft with 120 degree water. Anyone have experience with this? I'm still looking on the web for this and haven't found anything. Apparently this is particularly useful with the Altherma, which I've learned qualifies for the 30% federal tax credit if solar hot water is installed --if 55% of domestic hot water is solar generated.

if you are at design temp and sending water out of your boiler at 150*F and returning 130*F you get 755 BTU per foot and your boiler should be in condensing mode almost all the time. 140*F coming back at 120*F you get 651 BTU per foot. this is at 4 GPM

How many hours per year does outside temp get down to design temp? Most of the heating season outside temp is higher than design temp.

If you have the wall space and the money install bore baseboard and run the system at lower supply temps.

I have Slant/Fin Baseline 2000 baseboard that I use low temperature water in. It is the 3/4 inch size, but it also comes in 1/2 inch. I run water between 110F and 135F in it. It gives out from 150 to 275 BTU/hour/foot at these temperatures. I have 14 feet of it in each of two rooms. Works fine in New Jersey.

because you are going to have to have 1 foot of board for each 1 linear foot of exterior wall space, and that includes the front and back doors :-)

Seriously, if you want to extract btu's from water at that temperature, you are going to have to FORCE them into the air, i.e. use a fan coil unit of some sorts.

The alternative is to go with radiant ceilings, walls and floors where applicable. This will also allow you to do radiant cooling.

Look at Warmboard's new R board which was specifically designed for retrofit applications. Click on the Warmboard link to the right hand side of these web pages for more information. Warmboard delivers true radiant comfort, which is incomparable to convective heating, which is what you would get from baseboard or fan coil units.

If you are looking for cheap heat, go convector. If you are looking for inexpensive radiant comfort, buck up and step up to radiant emitters, which work EXCELLENT with the low temperatures you can expect from an A.S.H.P.

Until you've experienced the difference, its a hard concept to sell. Once you have experienced it on a first hand basis, it is EASY to relate the experience to your customers.

ME

It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.

buy the Altherma, then they dang well should have enough to polish off the job with some in floor heat. If this is not the case, however, the altherma also comes in a high temp version. I don't know if they brought them across the big drink yet. Just keep in mind, When you go to these training classes, the teachers often have a two pronged approach. They train you on the product but they also try to convince you they have the best tool for your job. I would hate to go out working with only one tool on the truck.

I have been led to believe that the cost of an altherma system --just talking heating and DHW for now--is on a par with a new mod-con installation with a more rapid ROI. (est. COP of 2.5 to 3.5) Add that to the federal tax credit of 30% if a percentage of DHW is solar-generated (the 30% credit can offset the added solar-related install).......

Thanks very much for the warmboard suggestion and baseboard advice. In a 1924 house with 2x oversized rads I'm loathe to take them out. No contractor has given me real Altherma numbers yet, but if I can combine this with an attic hydronic fan coil for existing central AC ducts, remove heating combustion in the house, remove negative air pressure from this old non-sealed combustion 3x oversized boiler for the price of a mod-con install which I'd have to consider anyhow, Altherma may be a good ticket--if the calculated KW hours add up right. Or so it seems to this HO.

The other thing I've never liked about baseboard no matter what the btu yield is that except for the cast iron models, they don't retain heat like rads.

> Apparently this is particularly useful with the Altherma, which I've learned qualifies for the 30% federal tax credit if solar hot water is installed --if 55% of domestic hot water is solar generated.

The ex-product manager for the Altherma just posted a similar claim in another group. It's simply not true. That would be like Lennox saying it's SunSource heat pumps and air conditioners (sold with PV panels) fully qualify for the tax credit. Only the solar water heater would qualify. The law that enables Section 25D tax credits for solar water heaters specifically requires that eligible equipment must be SRCC certified.

the tax credit.... I concur with ginahoy that it's not a very good case. The geo tax credit being applied incorrectly is a bad case too, and people do it, but sooner or later nothing good can come of it.

as for the baseboard, there are no shortcuts to low temp baseboard design. Room by room load calcs must be done and baseboard sized. Rule of thumb is that you double lengths from 180 to 140 and you double again 140 to 120. Any high-output baseboard will perform like that "low temp" baseboard will. compare 200 degree output ratings (or any other same temperature rating) and you'll see what they can do compared to each other at least.

I also second mark's recommendation for radiant ceiling. it's cheap and low temp and invisible. as long as you have flat ceilings it's great. can be cheaper than panel rads or baseboard sized for very low temps. and if you're really looking for adventure, you can even cool with it... if you're working with people who know what they are doing there.

Back in the 70's, in the first iteration of the solar business I ran into folks taking an Olin flat plate solar collector only, no glazing, insulation or box. They would hang the plate under the porch and pump refrigerant to it and call it a "Solar Heat Pump" to qualify for the TC. I think the refrigerant would flash at about 52f, so, sure why not??? The plate never saw the sun.